12-57766019-C-T

Position:

• chr12-57766019-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM2 PP3_Strong PP5_Moderate

The NM_000785.4(CYP27B1):​c.374G>A​(p.Gly125Glu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000141 in 1,419,816 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CYP27B1 NM_000785.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 7.31

Genes affected

CYP27B1 (HGNC:2606): (cytochrome P450 family 27 subfamily B member 1) This gene encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. The protein encoded by this gene localizes to the inner mitochondrial membrane where it hydroxylates 25-hydroxyvitamin D3 at the 1alpha position. This reaction synthesizes 1alpha,25-dihydroxyvitamin D3, the active form of vitamin D3, which binds to the vitamin D receptor and regulates calcium metabolism. Thus this enzyme regulates the level of biologically active vitamin D and plays an important role in calcium homeostasis. Mutations in this gene can result in vitamin D-dependent rickets type I. [provided by RefSeq, Jul 2008]

CYP27B1 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.975
• PP5: Variant 12-57766019-C-T is Pathogenic according to our data. Variant chr12-57766019-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1659.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CYP27B1	NM_000785.4	c.374G>A	p.Gly125Glu	missense_variant	2/9	ENST00000228606.9	NP_000776.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CYP27B1	ENST00000228606.9	c.374G>A	p.Gly125Glu	missense_variant	2/9	1	NM_000785.4	ENSP00000228606.4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000141 AC: 2 AN: 1419816 Hom.: 0 Cov.: 31 AF XY: 0.00000142 AC XY: 1 AN XY: 703274

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000262

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.12e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Vitamin D-dependent rickets, type 1A Pathogenic:2

Pathogenic, no assertion criteria provided	literature only	OMIM	Mar 05, 1998	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Aug 02, 2023	Variant summary: CYP27B1 c.374G>A (p.Gly125Glu) results in a non-conservative amino acid change in the encoded protein sequence. This alters a conserved residue (HGMD) in which another missense variant (p.Gly125Arg) has been classified as likely pathogenic by a ClinVar submitters, suggesting this may be a functionally important amino acid. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 177120 control chromosomes (gnomAD). c.374G>A has been reported in the literature in a homozygous individual affected with pseudovitamin D-dependent rickets (Kitanaka_1998). These data indicate that the variant may be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein function, finding that the variant protein had no 1alpha-hydroxylase activity (Kitanaka_1998). The following publication has been ascertained in the context of this evaluation (PMID: 9486994). No submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.33
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.77	D
Eigen	Pathogenic	0.72
Eigen_PC	Uncertain	0.63
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.87	D
M_CAP	Pathogenic	0.39	D
MetaRNN	Pathogenic	0.97	D
MetaSVM	Uncertain	0.24	D
MutationAssessor	Pathogenic	3.3	M
PrimateAI	Pathogenic	0.88	D
PROVEAN	Pathogenic	-7.6	D
REVEL	Pathogenic	0.85
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.98
MutPred		0.86		Gain of catalytic residue at T128 (P = 0.0555);
MVP		0.94
MPC		1.5
ClinPred		1.0	D
GERP RS		5.0
Varity_R		0.98
gMVP		0.93

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs28934605; hg19: chr12-58159802;